Ceramic bodies, such as aluminum titanate and cordierite ceramics, may be used in a variety of applications. For example, such bodies are viable for use in the severe conditions of exhaust gas environments, including, for example as catalytic converters and as diesel particulate filters. Among the many pollutants in the exhaust gases filtered in these applications are, for example, hydrocarbons and oxygen-containing compounds, the latter including, for example, nitrogen oxides (NOx) and carbon monoxide (CO), and carbon based soot and particulate matter.
Ceramic bodies exhibit high thermal shock resistance, enabling them to endure the wide temperature variations encountered in their application, and they also exhibit other advantageous properties for diesel particulate filter applications, such as, for example, high porosity, low coefficient of thermal expansion (CTE), resistance to ash reaction, and a modulus of rupture (MOR) adequate for the intended application.
With engine management schemes becoming more and more sophisticated, and with catalyst compositions ever changing, there exists a need for the ability to vary or tailor the properties of these ceramic bodies, for example their pore size, porosity, pore size distribution, and microstructure. Moreover, there is a need for methods to make ceramic bodies having these desirable properties. Additionally, there is a need for methods to reduce pore size variability in ceramic bodies and/or reduce process variability in making ceramic bodies.
While pore formers may be selected to produce a range of porosity and/or pore size in a ceramic body based on their shape and size, they may be expensive and can make extrusion and drying difficult, including often requiring complicated firing cycles to burn out the pore former without cracking the underlying parts.
The inventors have now discovered novel ceramic-body-forming batch materials, ceramic bodies, and methods of making the same that may allow for the ability to vary or tailor the properties of these ceramic bodies, for example their pore size, porosity, pore size distribution, and microstructure.